Biometric determination is generally defined as the process of measuring and using one or more physical or behavioral features or attributes to gain information about identity, age, or sex of a person, animal, or other biological entity. As well, in order to ensure security, the biometric determination task may include further tasks that ensure that the sample being measured is authentic and being measured on a living being. This latter test is referred to as a determination of liveness.
There are two common modes in which biometric determinations of identity occur: one-to-many (identification) and one-to-one (verification). One-to-many identification attempts to answer the question of, “do I know you?” The biometric measurement device collects a set of biometric data and from this information alone it assesses whether the person is a previously seen (“authorized”) individual. Systems that perform the one-to-many identification task, such as the FBI's Automatic Fingerprint Identification System (AFIS), are generally very expensive ($10 million or more) and require many minutes to detect a match between an unknown sample and a large database containing hundreds of thousands or millions of entries. The one-to-one mode of biometric analysis answers the question of, “are you who you say you are?” This mode is used in cases where an individual makes a claim of identity using a user name, a personal identification number (PIN) or other code, a magnetic card, or other means, and the device collects a set of biometric data which it uses to confirm the identity of the person.
Although in general the one-to-many identification task is more difficult than one-to-one, the two tasks become the same as the number of recognized or authorized users for a given biometric device decreases to just a single individual. Situations in which a biometric identification task has only a small number of entries in the authorization database are quite common. For example, biometric access to a residence, to a personal automobile, to a personal computer, to a cellular telephone, and to other such personal devices typically require an authorization database of just a few people.
Biometric identification and verification is useful in many applications. Examples include verifying identity prior to activating machinery or gaining entry to a secure area. Another example would be identification of an individual for matching that individual to records on file for that individual, such as for matching hospital patient records especially when the individual's identity is unknown. Biometric identification is also useful to match police records at the time a suspect is apprehended, but true identity of the suspect is not known. Additional uses of biometric identification or verification include automotive keyless start and entry applications, secure computer and network access applications, automated financial transaction applications, authorized handgun use applications, and time-and-attendance applications. In general, protected property will be the term used to describe all of the goods, places, services, and information that may require biometric authorization to access.
Current methods for biometric identification are manifold, but some of the most common techniques include fingerprint pattern matching, facial recognition, hand geometry, iris scanning, and voice recognition. Each of these technologies addresses the need for biometric identification to some extent. However, due to cost, performance, or other issues, each of the existing methods has advantages and disadvantages relative to the other technologies.
There are currently many personal electronic devices that are used to gain access to protected property but that do not include any biometric capability. For example, electronic fobs are commonly used to gain entry to automobiles and to activate commercial and residential alarm systems. Wristwatches such as the Swatch Access models can be used to purchase and download codes that allow easy entry to ski areas and other for-pay recreational sites. A wristwatch being sold by Xyloc permits access to computers, printers, networks, or other properly equipped hardware and systems when the watch is in the vicinity of the protected system. A small electronic device known as an iButton sold by Dallas Semiconductor can be put into a ring, key fob, wallet, watch, metal card or badge, that a person can carry and use to gain access to properly equipped doors and other protected systems. However, an unauthorized user can gain access to any of the property protected by these systems by simply obtaining a device from an authorized user. These devices do not have the capability to distinguish between authorized and unauthorized users and will work for anyone who possesses them. This deficiency represents a major security concern.
In U.S. Pat. No. 6,041,410, Hsu et al. disclose a personal identification fob that employs fingerprint data. This system is specified to contain memory to hold the fingerprint image, an image correlater, a communication means employing a cyclic redundancy code, and a “door” that is controlled by the biometric system and allows access to protected property. Hsu et al. generalize “door” as a means to access protected property including a building, a room, an automobile, and a financial account. The method disclosed relates to a door that protects property and its interaction with the fob, including a “wake-up” message and a series of steps to collect the biometric data and compare it with reference data, determining a match, and then actuating the device to provide access through the door.
One company that currently sells a personal identification unit is affinitex, a division of AiT, and the product name is VeriMe. Because of the size of the fingerprint reader incorporated in the VeriMe product as well as the batteries and control electronics, the unit is relatively large and is intended to be hung around the neck like a pendant. In contrast, a long-standing desire of many in the biometric community is a biometric technology that can be discretely incorporated in a piece of jewelry such as a wristwatch (for example, see Biometrics; Advanced Identity Verification, Julian Ashbourn, Springer, 2000, pp. 63-4).
There are a number of known biometric products and technologies that rely on optical images of various tissue sites to perform a biometric determination. For example, in U.S. Pat. No. 4,537,484, Fowler, et al. describe an apparatus for collecting a fingerprint image using optical techniques. In U.S. Pat. No. 6,175,407, Sartor describes an apparatus for collecting a palm image using optical techniques. In U.S. Pat. No. 5,291,560, Daugman describes a method for collecting and processing an optical image of the iris. In U.S. Pat. No. 5,793,881, Stiver et al. describe a system and method for collecting an image of the subcutaneous structure of the hand using an imaging methodology. However, all of these technologies generate and use images of the tissue as the basis for a biometric determination. The use of imaging generally requires high-quality expensive optical systems and an imaged region that is of sufficient size to capture the necessary biometric detail. If the imaged region is made too small, the biometric performance of these imaging systems degrade. For this reason, contact imaging systems such as fingerprint and palm readers require a relatively large, smooth, accessible surface, limiting the range and form of products in which such systems can be incorporated. Finally, because the determination of a match between enrolled images and the test images is dependent on the orientation of the two images, such biometric systems have to correct for these positional effects. For this reason, biometric systems that rely on imaging techniques require a significant computational power and a sophisticated algorithm to correct for image displacements, rotations and distortions, which leads to increased system cost and increased time required for user authentication.
As an alternative to imaging techniques, the use of spectral information for biometric determinations is disclosed in U.S. patent application Ser. No. 09/832,534, filed Apr. 11, 2001, entitled “Apparatus and Method of Biometric Identification or Verification of Individuals using Optical Spectroscopy”, which is a continuation-in-part of U.S. patent application Ser. No. 09/415,594, filed Oct. 8, 1999, entitled “Apparatus and Method for Identification of Individuals by Near-Infrared Spectrum”. The equipment used to perform the measurements disclosed in these applications was based on relatively large and expensive multi-purpose laboratory-grade commercial spectrometers. The family of techniques disclosed in these applications is referred to as spectral biometrics. The disclosures of these applications are incorporated herein by reference.
It is well known that tissue spectra are generally affected by both the absorption and scattering properties of the tissue. For many spectral measurement applications the portion of the measured spectra that represent the absorption characteristics of the tissue are more important for the measurement rather than the effects due to scatter. One technique for separating the two effects is known as radially resolved diffuse reflectance spectroscopy, which is based on collecting multiple measurements with different source-detector separation distances. This collection of data provides enough information to estimate and separate effects due to scatter and absorption (see Nichols, et al., Design and Testing of a White-Light, Steady-State Diffuse Reflectance Spectrometer for Determination of Optical Properties of Highly Scattering Systems, Applied Optics, Jan. 1, 1997, 36(1), pp 93-104). Although the use of multiple source-detector separations is a well-known technique for analyte measurements in biological samples, the use of similar measurement configurations for spectral biometric determinations has not been previously disclosed.
There is a need for an inexpensive, rugged and small spectrometer to perform spectral biometric determinations. One method that can be used to construct such spectrometers is based on using multiple discrete light sources such as light emitting diodes (LEDs), laser diodes, vertical cavity surface emitting lasers (VCSELs), and narrow band optical filters coupled to a broad-band optical source such as an incandescent bulb or blackbody emitter, operating at different wavelengths to illuminate and measure the optical properties of the sample at each of these wavelengths. These types of spectrometers are known and used for collecting spectrometric information for many applications. For example, in U.S. Pat. No. 3,910,701, Henderson et al. disclose a spectrometer that incorporates a plurality of LED sources for measuring a variety of biological samples. In U.S. Pat. No. 4,857,735, Noller discloses a spectrometer using one or more LEDs to measure solution samples. In U.S. Pat. No. 5,257,086, Fately et al. disclose an optical spectrometer having a multi-LED light source incorporating Hadamard or Fourier frequency encoding methods. However, there is a need for a small, rugged, and inexpensive spectrometer with designs that are optimal for biometric determinations.
As part of the biometric determination task, there is a need for ensuring that the sample being used for the biometric determination is alive. For example, U.S. Pat. No. 5,719,950 to Osten et al. disclose a method and system to combine a biometric-specific measurement such as fingerprints, palm prints, voice prints, etc with a separate measurement of a non-specific biometric parameter such as skin temperature, pulse, electrocardiogram or tissue spectral features to ensure the liveness of the sample.
In addition to performing a biometric identification or verification and ensuring that the sample being measured is living tissue, there may also exist a need to determine an estimate of the age, sex, and other demographic characteristics of the person under test as part of the biometric determination task. For example, the U.S. Federal Trade Commission recently established a commission to examine the issue of remotely determining age of a person who is attempting to access a web site in order to block access by children to inappropriate sites. The Commission on Online Child Protection (COPA) heard testimony on Jun. 9, 2000 that indicated that then-known biometric techniques could not be used to aid the determination of a person's age based on any known biometric features.